<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>

    <style>
        div{
            width: 100px;
            height: 100px;
            border: 1px solid red;
        }
        #d1{
            /*margin-top: 50px;*/
            /*margin-left: 50px;*/
            /*margin: 50px;*/
            /*margin: 50px 100px;*/
            /*margin: auto;*/
            /*margin: 10px 20px 40px 30px ;*/
            margin-bottom: 50px;
        }
        #d2{
            /*上下相邻彼此添加外边距，取最大值*/
            margin-top: 50px;
        }
        span{
            border: 1px solid blue;
        }
        #s1{
            /*左右相邻彼此添加外边距 外边距相加*/
            margin-right: 50px;
        }
        #s2{
            margin-left: 0px;
        }
    </style>

</head>
<body>

<span id="s1">span1</span>
<span id="s2">span2</span>
<div id="d1"></div>
<div id="d2"></div>

</body>
</html>